Hach DR/850 Procedures Manual page 38

CHEMICAL ANALYSIS INFORMATION
Figure 9 Standard Additions Decision Tree
No
D
Is the Procedure in
Use Correct?
No
Use Correct
Procedure and
Repeat B
E
Are the Reagents Working Properly?
No
Repeat B with
New Reagents
Did a Single Standard Addition Give the Correct Recovery?
No
A
Are
Interferences
Present?
No
B
Do Multiple
Standard Additions
On DI Water Give
Correct Recovery?
F
Yes
H
Is Instrument Apparatus Working Properly?
No
Repair/Replace
Instrument Apparatus
and Repeat B
, continued
Yes Yes
C
Do Multiple Standard
Additions On Sample
Give Uniform Increments?
No
G
Analysis May
Analysis
be Correct
Is Incorrect
Yes
I
Standards Defective
Repeat B with New
Standards
38
Yes
J
Are
Interferences
Present?
No
K
Analysis
Is Correct
Yes
Yes
Yes